Reverse-current relay.



G. A. BUHNHAM.

REVERSE CURRENT-RELAY.

APPLICATION HLED 1AN.24|1913.

Patented' Ja1 1.30,1917.

3 SHEETS-SHEET l.

mA. BURNHAM.' REvEasE CURRENT anni I A'PPucmou rLu`1An.-24. rea.. n l "y 1,213,835. Patented Jan. 30,1917.`

a sedans-suene.

UNITED sTA'rE 'GEORGE A. BURNHAM, OF SAUGUS, MA

s entranti? oFF-ICE.

ssAcHUsETTs, AssiGNon. BY ssiGN- `MENTS, 'ro GENERAL ELECTRIQ COMPANY, A conPoiiATioNo NEW' Yoan,"

REVERSE-CURRENT RELAY..

V i Application ledJanua .if BUR The proper operation and in a great measure the continuity of service of electric accuracy and characteristics of 4the relays forming a part of the protecting apparatus.f Heretofore where `several 'transmission lines or feeders have been employed to carry current toVv and from a common set of bus-bars,

reverse-current relays have been employ yto disconnect the lines or feeders with whi they are associated, said relays adapted be operated by 4or upon the reversal of t current -or energy Some forms of ble deviceY Also. in order factorily on voltages even normal, the winding must be designed exert a considerable force at such voltages and still have suicient radiating surface prevent excessivelieating, vet the relay .55 usually arranged on a ranged continuouslyv inthe circuit which an important factor in determining l404 of the relay.

their potential-windings continuously the circuits are aiected by variations the power-factor conditions, y and are liable to operate on account of low power-factor rent flows in thel proper direction.

MV invention has 5 other being wound in opposite directions,

Specification of Letters Patent.

States, residof Essex and in said lilies or feeders. reverse-ci'irrent relay involve a differential-coil, and if a short cir- ;at that point drops the potential-windinuence on the operaresults in an unreliato provide a coil which will allow the relay to work satis-- slightlv below switch-board, and must necessarily 1 be small to occupy but little space. The ,potential-windings are arthe size Furthermore, relays having for its 'object the construction ot' `a reverse-current relay' whereb v these many objections are overcome, and involves the employment of two differential- Pateiited 12111.30, 1,917.

ry 24,1913. seriai 110.743.915. 1

one of the windings of each coil beingr included in a closed circuit ot' a current-transt'ormer which is associated with one of the feeder-wires and the other winding of each an of circuit of a potential-trans ormerarranged in shunt with the feeder-wires, and switchopeiating means. which is normally ybiased to open position and adapted to be moved to closed position by oraipon reversal .of the current in the diti'erential-coils, and upon closure ot' the open transformer circuit, and a relay-switch or equivalent electro-responsive means for closing said open distribution systems is dependent upon the ed ch to he eluded in or controlled by the closed transformer-circuit. H l

)Iy invention. however` 'comprehends'the employment ot a single `differential-coil having one of its windings arranged in an open transfoimer-circuit, and a relayswitch or equivalent electro-responsive to is `responsive to variations in the current value of the closed transformer-circuit.

Figure l is a front elevation of the reverse current relay. Fig. '2 is a side elevacircuit including the reverse current relay. Fig. 5 is a modified form of relay-switch which may be employed. Fig. 6 a modified form of reverse current relav which may be employed.

The electric distribution system here shown for the sake ot' illustrating my invention is a vsingle phase system. but 'it willbe understood that the invention is adapted for any use of the polyphase systems by a simp le duplication of the parts. In the system here shown, 10 and l2 represent the bus-bars at` the generating station; 13 and 1l the bus-bars `at the sub-station; 16, 1 7 and 1S. 19,the feeder-wiresconnecting said busbars. As represented in `Figs. 1 .to l. the reverse current relay comprises essentially' two a diagram of a 445 which is obiectionable. Furthermore, the

' relay is liable to operate on oval-loads or a differential-coils, said coils eacli consisting short `circuit of greatvalue when the euroi' a current-winding Q0 and zl, and a poon stationary cores 723, Each differential-coil has an armature made as a movable core-piece 24, 34, and said core-pieces are attached to the extremities of a walkingbeam 40, pivoted at 41, and bearing the mov-- in he coil being included in an o )en transformer traiis'fornier-circuit. the coil of which is 1nmeans to control said open circuit, which tion. Fig. 3 is a plan view. and Fig. -L isdisposed, so that the flow of current through' them isl in the same direction. The potential-windings are made alike also and are arranged in series in a transformer-circuit 55, of a potential-transformer 56, the p-imary of which is arranged in multiple tween the feeder-wires and is, therefore, shunted,` but said potential-windings are wound in opposite directions, so that the current flows through one of them in the same direction that the current Hows through its associated current-winding, and flows through the other in the opposite direction to the flow of current through its asso- .ciated current-winding. The transformerelrcuit 55 is normally open. hence the potential-windings are normally inactive, but the current windings are active, and being made alike will exert like pull upon their cores. One of the coils, however, has

a longer air gap than the other so that when the strength of one current-winding equals the strength of the other, the tendency is for the walking-beam 40 to rotate counterclockwise until it strikes the limiting-stop 47, and thereby move the movable switchmember 42 away from the switch-member 43 and open the circuit of the tripping-coil. Thus the switch-operating means is normally biased to open position. Said open transformer-circuit 55 is adapted to be closed as here shown by a relay-switch, the coil 60, of which lis included in the transformercircuit 50, in series relation with the currentwindings. and the movable switch-member 61, of which is adapted for movement into and out of engagement with the stationary switch-members 62, 62, which are connected in the transformer-circuit 55, thereby to close said transformer-circuit 55, upon attractive movement of the armature of the coil 60. The coil 60, may be. made as adifferential-coil as represented in Fig. 5 the two coils being supplied by the series and potential transformers 51. 56, and in such case it would be infiuencedbv a reversal of the current passing through the feederwires, but the simple form of coil shown in Fig. 4 is preferred. as it vresponds to curlrent fiowing in either direction and movement of its armature is dependent upony thevalue ofthe current. Y.

including the As long as the current passes through the feeder-wires in the proper direction irrespective ofthe "alue of the current the reverse current relay will not operate, thatis is to say, the parts 4will remain in the biased position shown in Fig. 4, for the reason tliat any increase of current in the transformer- Ycircuit 50 will result in a correspondingly increased pull on the walking-beam produced by the current-windings only. Fur.- thermore,.if the current is of such value' -as to cause the relay-switch to operate and close the transformer-circuit 55,V momentarily, or as long as a heavy'overload or short circuit lasts. the potential-windings being arranged with relation to the currentwindings, as shown in Fig. 4, it will be seen that the potential-winding 30, actsto. assist thefcurrent-winding 20 in holding its core 24, .while the potential-winding 31` is so related to the current-winding-21 that lit op-V poses the pull on its core 34, and therefore movementof the? same is prevented.

4If a short-circuit should occur on the feeders 16, 17, at say 70, current will ow to the short-circuit in two directions, one over the bus-bars 10, 12, feeders 16, 17, passing through that portion of the circuit in the proper direction, and it will also flow from the bus-bars 10, 12, over feeders `18, 19,.and bus-bars 13, 14. in the proper direction, and then through the feeders 16, 17, and shortcircuit, including the current-transformer 51, in the opposite direction. This will result in a reversal of the flow of current on the current-windings 20, 21, and if the reversal is of such intensity as to'cause the relay-switch to close the transformer-circuit 55, then the potential-windings will be vrendered active and the potential-windings 31 will assist the current-winding 21, and the potential-winding 3() will oppose the current-winding 20, andv as a result the walk- A ing-beam w1ll be moved to move the switchmember 42 into engagement with the switch 43, and close the circuit of the tripping-coil and allow said tripping-coil to become energized and'o'perate to open the switch 46. The result is a sudden diminution ofthe current in the feeders 18, 19. Thus itwill be seen that by keeping thecircuit of the potential-windings open. enables the use bf a value of current in the potential-windings which is very much higher than would be the case if said windings were arranged continuouslyin the circuit. when speaking of potential-windings of given dimensions, and enables the employment of a very much stronger winding. Furthermore, it will be understood that the potential-winding is powerful at very low voltages. In case a shown, in connection with each set of feeders, it will be observed that when the above described conditions exist the time-limit reltime-limit relay is also employed, as here lay 75, which governs the opening of the switclrt is started to cause the tripping of the switch, and after a short period of time will trip the switch 7G, thus the feeders 16,-

17, which are short-circuited will be disconnected from the distribution system .ind the continuity of the circuitwill be maintained over the feeders 18, 19. The reverse current relay which controls the switch 80 will not operate because the current passing through that portion of the circuit is in the normal direction, and the time-limit relay 85, which controls the switch SG is adjusted for the same time as therelay 75, but the current in said relay 85 is reduced instantly to that value required to supply the translating-devices in the circuit 90, 91, While the timelimit relay 75 has a very high value of curient passing through it caused by the shortcircuit 70 will move very milch faster andv cause the switch 76 to trip before the switch 86 vis tripped.

Referring to Fig. 6 of the drawing, asin-f 181 of which is arranged in theope'n trans- :former-circuit. The switchfoperatinv controlled by the diilerei lfoils of a walking-beam 190. edfat '191"""and bearing'. a movable is ch-member 192 v adapted to close uponj-tlie stationary switclb member 193 androne end of said walkingbeamis connected with the movable core 174 of the diiferentialcoil and the other end thereof has connected with it a dash-pot 194 for reta-rding its movement in one directionand also has a weight 195 for assisting in moving it in the oppositedirretion against a limiting-stop 196, and also serve as`a current calibration. tially the same'results are obtained as in the construction illustrated in Figs. 1 to 4. Although ashere shown the tripping of the switches is accomplished by a tripping-coil in an open circuit it is obvious that the tripping-coil may be arranged in a closed circuit.

In-theabove specication and in the following claims I have employed such terms as current flowing in either direction reverse current relay and reversal ot current `in their commonly accepted sense when alternating currents are considered; namely, as indicative of the direction in which energy ows in the circuit tewhich the" relay is connected.,

I claim: 1. A reverse current relay comprisin 'a pair of diiferential coils', a switch contro ed In this instance substan-` by said coils, normally biasedto the open position and movable to the closed position upon reversal of current, said coils having two windings, one of which is normally in-` active and means controlled by the current through the second winding for rendering said first winding active.

A reverse current relay having windings arranged iii differential relation, a rockswitcli governed by Said windings normally biased by the relay current to op'en position' and adapted to be moved to. closed position upon reversal of the currentfone of the windings being included 'in an open circuit, and means to close said circuit, substantially as described. V

A reverse current relay having Wind,- ings arranged in differential relation, a rckl I switch governed b v said windings normally biased b vtlie current coils ofthe relay to one position and adapted to be 'movedto another position upon reversal of the current, one of the windings being normally inactive,'and" means operated upon an abnornial condition of the circuit to render saidv winding active, substantially asdescribed.

A reverse Vcurrent relay comprising a paiiof.differential-coils, a rock-switch con` trolledy by .tlicacoils normally biased to one posi onand adapted to be moved toanother po upon reversal of the current, one iig yof each of said coils being normally vet-and means controlled by an abnor mal-condition of the circuit to render said windings active, substantially as described.-

A reversecurrent relay comprising a pair of differential-coils, a rock-switch upon the arms of which the coils act, normally biased to open position and 'adapted to be moved to closed position upon reversal of the current. one winding of each-of lsaid coils being included in ano-pen cir'c" nd means to close said circuit, substant described. 5

6. A reverse-current relay comprisin s. pair of differential-coils, a: balanced switch controlledby them, normally biased by the current of the coils to open position and adapted to be moved to closed position upon reversal of the current,'one wind-ing of each 115 of said coils being included in an open circuit, and electro-responsive means to close said circuit which is responsive to the current of said coils, substantially as described.A

7. A reverse-current relay comprising a pair ofdtferential-coils, a rock-switch controlled by them normally biased by the cura rent coils to open position and adapted to.' be moved to closed position upon reversal of the current, one winding f'each of said 1 25 8. A reverse-.current relay comprising a pair .of diferentiabcoils each havin two windings, the windings of one coil'being S0 arranged that under normal conditions current will how in the same direction in both and the windings of the other coil being so arranged that current will iow in opposite directions in the two windings, switch operating-nigans controlled by said coils, normally biased to-open position and'adapted to be moved to closed position upon reversal of the current, one windingof each coil being included in an open circuit, and means to close said circuit, substantially as described.

9. A reverse-current relay comprising a pair of di'erentialfcoils each having two windings, the windings of'one coil being so arranged that current will flow in the same direction ini-.both and the windings of the other coil being so arranged thatcurrent will flow in opposite directions in the two windings, switch operating-means controlled by said coils, normally biased to open-position and adapted to be movedto closed position upon reversal of the current, one winding of` each coil being included in an open circuit, and electro-responsive means to close said circuit which is responsive to a current of a, predetermined value,substantially as described. 3.

10. Al reverse-current relay comprising a pair ofcurrent-windings so arranged that -current willl flow through both in the same direction and a pair ofcpotential-windings so arranged that current will flow in oppo site directions in the two, associated together to form a pair of differential-coils having a preponderant bias on one side. the currentwindings beingA active when the current is flowing in the proper direction and alsorupon reversal thereof, and thepotential-windings being normally inactive and when rendered active, adapted to assist one of the currentwinding and nullify .the other, electro-responsive meansto render active said potential-windings and ,controlling-means for the circuit operated by said coils, substantially as described.

11. A reverse-current relay comprising a pair of current-windings so arranged that current will kflow through both in the same direction and av pair of potential-windings so arranged that current willflow in opposite directions in the two, associated together to 'form a pair'of differential-coils having a preponderanat` bias on one side, the currentwindings being. arranged in series relation in a. closed transformencircuit and the p0- tential-windings being arranged in series relation in an open. transformer-circuit, electro-responsive means tol close said open transformer-circuit. therebyr to .cause one 4of the potenti al-windin'gs to assilt its associated current-.winding and the lother potentialto nullify its associated current.a

laisses winding, and switch-operating means operated by said differential-coils, substantially as described.

A reverse-current relay comprisinga pair of current-windings so arranged that current will flow throu h'both in the same direction and. a pair o potential-windings so arranged that current will flow in op osite directions in the two, associated togetlier to form a pair of differential-coils, the current-windings being arranged in series relation in a closed transformer-circuit and the potential-windings being arranged in series relation in an open transformer-circuit, a relay-switch to close the open transformercircuit, the coil of which is arranged in the closed transformer-circuit, and switch-operating means operated by said diii'erentialcoilss ub stantially as described.

13. A reverse-current relay consisting of a pair of differential-coils, each coil comprising a current-winding and a potentialwinding, the current-windings being alike and so arranged that current will flow through both in the same direction and the potentialwindings being alike and so arranged that current will flow in opposite directions in the two. movable cores for said coils, 4switch-.op'erating means governed by.

i is arranged in series with the current-windings and lthe switch of which is arranged in the circuit of the potential-coils. whereby the potential coils are rendered active upon operation of said relay-switch, substantially as described.

14. A reverse current relav comprising a pair of differential coils. each having serarate currentand potential windings. the windings of one being so arranged that current will flow through both in the same direction. and the windings of the other being so arranged that current will flow in opposite directions in the two. a rock switch controlled b v them and normally7 biased by the current coils to o pen position. the current windings being arranged in series relation in a closed transformer circuit and the potential windings being arranged in series relation in an open transformer circuit. the current winding being active .when current is flowing in either direction. and 'a relay switch responsive to current of a predeter. mined value in either direction for closing the open transformer circuit. the coil of said relay switch being included in series with the current windings.

15. A reverse current relay comprising a pair of diierential coils each having separate current and potential windings. the

windings of one being so arranged that cuty rent will flow through both in thesame `cli-'nu rection and the windings ofthe other being so arranged that current will ilow in opposite directions in Itlieftwo, switch operating means controlled, by them and normally biased by the` current windings to open position, the current windings being arranged in series relationin a closed transformer ciry cuit, and the potential windings beingarranged in series relation in an'open trans v former circuit, the current windings being active when current is flowing in either direction and a relay switch responsive to current of a predetermined value in eitherdirection for closing the open transformerv circultgthe coils of said `relay switch being.

included .in series with the current windings. 4 16.y A reverse current relay comprisinga air of differential coils, leach coil comprisinga current winding and a potential winding` the current windingsbeing alike, and

' soia -anged that current will flow through andfnormally both yin the same direction and the potential. being alike andI so arranged that will flow in opposite directions in biased by the current coils to the current windingsbeing ,open position,

in a closed trans-` arrangedin series relation formercircuityand the potential windings being arranged in seriesrelation in an open transformer circuit, being` active .when current` is flowingv in either direction and means controlledby the currentl through the current windings for closing ,theopeii transformer circuit.

'. A"reverjse `currentyrelay comprising 'a erential coils, each rcoil comprising rrentfiwindingsxbeing alikeand so art current will flow through both eine direction, and nthe potential bein windings being arranged in series relation in a, closed transformer circuit andthe potential windings being arrangedin series relation in an open transformer circuit, the current windings b eingv activewhen current -is flowing in both directions and a relay switch, responsive to currentof: a" predetermined value in either diranged in the two,A a rock switch controlled the two, af rock switch controlled by them a the current windings "'indin and a potential winding,

4 alike and so arranged thatl vill ow in opposite directions in the tw'og'a rock switch controlled byk said coils, the current relay comprising a controlled by them,

that current will flow in opposite di i bythem and normally biased by thecurrent coils to open position, the current windings beingarranged iniseries relation in aclosed transformer circuit and the potential wind-r ings being arranged in series relation in an' open transformer circuit, and a relay switch,

responsive to current of a' predetermined value in either direction for closing the open transformer circuit, the coil of said relay switch being included in serieswith the current windings.

19. A reverse current relay comprising a pair of dierential coils, each. coil compris` ing a current wiiidingand a potential wind# ing, the current windingsr being` alike' and similarly wound and the potentialwindngs being'` alike and oppositely wound, the'cur` rentwindings being normally active and the'. potential windings normally inactive,a rock-` switch `controlled `by the coils'and normally biased by the current coilsfto openposition` andimeanscontrolled by the currentthrough the current windingsfor rendering thepotential windings active.

20. A reverse current relay comprisingV a p air of current' windings so arranged thatv vcurrent will flow through both injthe samey direction and a pair of potential windings so arranged that current will flow inopposite directions in the two, saidwinding's be` ing associated together to form. a pair of differential coils, a, rock switch controlled by them and normally biased by the currentcoils.

to open position, the current windings being arranged in series relation in a closed transformer circuit and the potential windings being arranged in series relation in an opei transformer circuit, and means yfor closing said open circuitv which is responsive tocurrent ofa predetermined value ineither di rection.

21. A reversek currentrelaygcomprising a pair of differential coilsl,a balanced switch controlled by said coils Aand normallyrv biased to the open position. by the current in -said coils, said coils having two separate ,windings, one of which 'is normally connected inl an Aopen transformer circuit and means controlledby` current through kthe closed circuit and re-` sponsive to current of a predetermined value for closing the open transformercircuit.

` 22. A reverse current relay comprising a "pair of current' windings sol arranged'v that flow through ,bothyin the same potential "windings will flow, in `oppocurrent will direction and a pair of so arranged that current site `directions inl tli'e two, ing associatedy together ton form a lpair differential ycoils, Ifswitch"l operatingy t means relation aclosed transformer circuit, an

which is normally connected in' a closed transformer circuit and the other ofv and normally vbiasedby the currentr windings. to openk position, the current windings being arranged in seriey saidwindingsbey .the potential windings being arranged in determined value in either direction for closing the open transformer cii'cui `Q3. A reverse current relay comprising a, pair ofcurrent windings so arranged that,vv

current will flow through both in the same direction and a pair of potential windings so arranged that current will flow in opposite directions in the two, said windingsl bcing associated together to form a pair of differential coils having a preponderant bias on one side, the current windings being tirranged in series relation in a closed transformer circuit and the potential windings being arranged in series relation in an open transformer circuit, the current windings being active when current is flowing in either direction and means controlled by the current through the current windings for closing the opentransfornier circuit.

24. A reverse current relay comprising a -pair of currentwindings so arranged that current will flow through both in the same.v direction 'and a'pair of potential windings so arranged that current will flow in opposite directions in the two, said windings being associated together to form a pair of' differential coils, the current windings being arranged in series relation in a closed trans'- former circuit and the potential windings being arranged in series, relation in an open transformer` circuit, the current windings being active when current is flowing in either direction, a rock switch controlled by said coils, and a relay switchfor closing the open transformer switch, the coil of said relay switch being included in series with the current windings.

:25. A reverse current relay comprisin a pair of current windings so arranged t at current will flow' through both in the same direction and a pair of potential windings so arranged that current will fiow in 0p osite directions in the two, said windings ieing associated together to form a pair of differential coils having a preponderant bias on one side, the current windings being no rmally activev when current is flowing in either direction, and the potential windings normally inactive and means controlled by current through the current windings, and res ,onsive toV current of a predetermined va ue for rendering thepotential windings active.

26. A reverse current relay comprising a pair of differential coils having a reponderant bias on one side, said coils having two separate windings, one of which is normally' connected in a closed transforme the other of which isnorinalfl an open transformer cii'ciiitan. We trolled by current through'tlic,closed I and responsive to current of a predeter value for closing the open trans-f 'Y cuit. 2T. A-f reverse current relay comprising a p'air of differential coils having afprepon- `derant biason one side, saidccils lhaving two separate windings, one of which isn'orinally `active and the other of which is normally inactive and means controlled by curi-.ent through the active windingand 'responsive tocurrent of a predetermined value for rendering the other winding active.

Areveise current relay, cominising a pair of differential coils, a"`bala'n"` `d switch controlled by said coils. said coils having current windings normally connected in a closed transformer circuit and potential windings normally connected in an open transformer circuit and means controlled by current through the current winding and responsive to current of a predetermined value in either direction for closing the open transformer circuit.

A reverse current relay comprising a pair of similarly wound current windings and a pair of opposite'ly wound potential windings associated together to/'form a pair of differential coils, a balanced switch controlled by said coils and normally biased thereby to open position, the current windings being arranged in series relation in a closed transformer circuit and the potential windings being arranged in series relation in an open transformer circuit, and means for automatically closing lsaid open circuit upon'i the occurrenceof abnormal 4conditions in the circuit to which the relay is connected.

30. A reverse current relay comprising a pair of coils each having two windings, the windings being so arranged that under no1'- mal conditions the effect of the two windings in one of the coils is cumulative and in the other coil differential.

31. A reverse current relay comprising a pair of coils, each having two windings, the

windings being so arranged that under norl mal conditions the effect of the windings in the first coil is cumulative and in the second coil differential, and under abnormal conditions the effect in the first coil is differential and in the second coil cumulative.v In 4testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses. -v

GEORGE A. BURNHAM. Witnesses:

D. M. SHIFFERT, i E. C. HATERHOUsi-i.

We! d this patent my' be obtained for ive cents/"each, by addressing the Comnlnlon'cr "of Patents, .wumummcr v 

